Not Applicable
This invention relates to a printhead chip for an inkjet printhead. More particularly, this invention relates to a printhead chip for an inkjet printhead, which incorporates covering formations for actuators of the printhead chip.
As set out in the above referenced applications/patents, the Applicant has spent a substantial amount of time and effort in developing printheads that incorporate micro electromechanical system (MEMS)xe2x80x94based components to achieve the ejection of ink necessary for printing.
As a result of the Applicant""s research and development, the Applicant has been able to develop printheads having one or more printhead chips that together incorporate up to 84 000 nozzle arrangements. The Applicant has also developed suitable processor technology that is capable of controlling operation of such printheads. In particular, the processor technology and the printheads are capable of cooperating to generate resolutions of 1600 dpi and higher in some cases. Examples of suitable processor technology are provided in the above referenced patent applications/patents.
The Applicant has overcome substantial difficulties in achieving the necessary ink flow and ink drop separation within the ink jet printheads. A number of printhead chips that the Applicant has developed incorporate nozzle arrangements that each have a nozzle chamber with an ink ejection member positioned in the nozzle chamber. The ink ejection member is then displaceable within the nozzle chamber to eject ink from the nozzle chamber.
A particular difficulty that the Applicant addresses in the present invention is to do with the delicate nature of the various components that comprise each nozzle arrangement of the printhead chip. In the above referenced matters, the various components are often exposed as a requirement of their function. On the MEMS scale, the various components are well suited for their particular tasks and the Applicant has found them to be suitably robust.
However, on a macroscopic scale, the various components can easily be damaged by such factors as handling and ingress of microscopic detritus. This microscopic detritus can take the form of paper dust.
It is therefore desirable that a means be provided whereby the components are protected. Applicant has found, however, that it is difficult to fabricate a suitable covering for the components while still achieving a transfer of force to an ink-ejecting component and efficient sealing of a nozzle chamber.
The Applicant has conceived this invention in order to address these difficulties.
According to the invention, there is provided a printhead chip for an inkjet printhead, the printhead chip comprising
a substrate; and
a plurality of nozzle arrangements that is positioned on the substrate, each nozzle arrangement comprising
nozzle chamber walls and a roof that define a nozzle chamber with the roof defining an ink ejection port in fluid communication with the nozzle chamber;
an ink-ejecting member that is positioned in the nozzle chamber, the ink-ejecting member being displaceable towards and away from the ink ejection port so that a resultant fluctuation in ink pressure within the nozzle chamber results in an ejection of ink from the ink ejection port;
at least one work-transmitting structure that is displaceable with respect to the substrate and is connected to the ink-ejecting member so that displacement of the work transmitting structure results in displacement of the ink-ejecting member;
an actuator that is connected to the work-transmitting structure, the actuator being capable of displacing the work transmitting structure upon receipt of an electrical drive signal; and
air chamber walls and a covering formation that is positioned over the actuator, the air chamber walls and the covering formation defining an air chamber in which the actuator is positioned, the roof, the work transmitting structure and the covering formation together defining a protective structure positioned in a common plane.
The invention is now described, by way of example, with reference to the accompanying drawings. The following description is not intended to limit the broad scope of the above summary.